PAEK polymers, including, for example, poly(etherketone) (PEK), poly(etheretherketone) (PEEK), poly(etherketoneketone) (PEKK), poly(etheretherketoneketone) (PEEKK) and poly(etherketoneetherketoneketone) (PEKEKK) polymers, are well known for their exceptional balance of technical properties, namely high melting point, good thermal stability, high stiffness and strength, good toughness and especially excellent chemical resistance. Therefore, PAEK polymers have potential for a wide variety of uses and their favourable properties class them with the best of the engineering polymers. For example, PEEK polymers have found increasing use in the manufacturing of high temperature and fire resistant films because PEEK has good elongation and good flexibility in thin sections such as films, or for coating of wires because PEEK has good flame resistance, and may be self-extinguishing with very low smoke.
One of the goals in the manufacture of PAEK polymers is that of enhancing their mechanical properties, such as strength, elongation at break and impact resistance.
Compositions comprising PAEK polymers and reinforcing fibers and/or additives are known in the art and can be referred to as “reinforced PAEK polymers”.
U.S. Pat. No. 5,844,036 (HOECHST CELANESE CORP) 1 Dec. 1998 discloses polyether ketone compositions comprising a polyarylether ketone, a reinforcing fiber, such as chopped glass and chopped carbon fiber fillers (col. 6, penultimate par.) and an immobilizing filler. The reinforcing fiber is said to provide high strength and stiffness, while the immobilizing filler is said to provide resistance to high temperature distortion. Immobilizing fillers of different nature are listed in this document; although mention is made of calcium carbonate, magnesium carbonate and boron nitride, there is no disclosure or specific suggestion to use such additives in combination with glass fibers. Table 1 reports the results obtained on different PEEK compositions, in particular two compositions containing a PEEK a glass fiber (Corning 731 ED) as reinforcing fiber and MICA as immobilizing filler. Moreover and more important, the amount of immobilizing filler is relatively high with respect to the total volume of the composition (from 30 to 45% vol. with respect to the composition; col. 7, lines 10 to 11).
U.S. Pat. No. 6,191,675 (HITACHI, LTD) 20 Feb. 2001 relates to a high-voltage transformer and discloses, inter alia, a bobbin material for the transformer, said bobbin material comprising a resin (e.g. a PEK) and an inorganic filler which may be a glass fiber, talc and mixtures thereof or another inorganic filler, e.g. calcium carbonate. The amount of inorganic filler in the compositions wherefrom the bobbin is obtained ranges from 10 to 70% wt with respect to the composition weight. In particular, Examples 14 and 18 in table 3 refer to compositions comprising a PEEK, a glass fiber and talc, wherein talc amounts to 20% wt of the compositions.
US 2004054021 (SERGEANT KENNETH MALCOM) 19 Mar. 2004 relates to a method of making a foamed material comprising heating a mixture which includes a polymer, especially a PAEK, and a decomposable material, especially magnesium hydroxide or aluminium hydroxide/hydrated alumina. The polymer may include reinforcement means, e.g. carbon and/or glass fibers. In this method, the decomposable material decomposes to produce water which in turn produces foaming within the polymeric material. Example 14 refers to an extrudate obtained from a PEEK comprising 30% glass fiber reinforcement blended with 10% wt of Mg(OH)2, MgCO3, CaCO3, FeO3, MnO4.
US 2006251878 (VICTREX MFG LTD) 9 Nov. 2006 relates to a polymeric material, for example a PEEK, and to a composite material comprising said polymeric material, which is said to have a lower viscosity of commercially available PEEK, while retaining similar mechanical properties to those of Victrex® PEEK 150. The polymeric material may comprise fibrous fillers, including glass fibers, and non-fibrous fillers, including, e.g. calcium carbonate. The amount of filler in the material can range from 20 to 70% wt with respect to the weight of the material.
US 2009048379 (SOLVAY ADVANCED POLYMERS LLC) 19 Feb. 2009 discloses certain polymer compositions endowed with chemical resistance and environmental stress rupture resistance, said compositions comprising a PAEK, a polyphenylene sulfone and a glass fiber in defined weight ratios. The compositions may include optional ingredients, including MgO and ZnO. Example 3, in particular, discloses a composition comprising Radel® R-5100 NT PPSU, Victrex® 150 P PEEK and Certainteed® 910 P glass fiber, a glass fiber having basic character.
EP 2067823 A (SOLVAY SA) 2 Dec. 2008 relates to a polymer blend comprising at least a PAEK and at least one high glass temperature sulfone polymer. This document discloses a control composition (Table 3) comprising Victrex® 150 P PEEK, Certainteed® 910 P glass fiber and ZnO.
CN 101220196 (NANJINH COMPTECH CO LTD) 16 Jul. 2008 relates to a PEEK composite material for the manufacture of valve seals which consists of polyether-ether-ketone, nanoparticles, filling materials and addition agent materials in definite amounts. The filling material can be a glass fiber and one of the nanoparticles is MgO.
CN 101508821 (UNIV NORTHWESTERN POLYTECHNICH) 19 Sep. 2009 discloses a PEEK composite used for a solid positioning head frame and a preparation method thereof. The composite may comprise a glass fiber and calcium carbonate.
CN 103013090 (CHONGQING CINWO PLASTICS CO LTD; CHONGQING 863 TRAFFIC ENGINEERING TECHNOLOGY CT LTD PARTNERSHIP; CH) 3 Apr. 2013 relates to a PAEK composite material that contains, in addition to a PAEK, a polyetrafluoroethylene resin, a fiber, e.g. a glass fiber, and a filler, including calcium carbonate and calcium sulphate. The composite may include boron nitride as solid lubricant.